Touch Screen Display Device

1. A touch screen display device, comprising: a plurality of pixels; and a plurality of touch sensing units, each touch sensing unit including a sensing transistor; a first touch electrode between a gate electrode and a semiconductor layer of the sensing transistor; a second touch electrode spaced from the first touch electrode; and a coupling portion to couple the first and second touch electrodes, wherein: each of the pixels includes an organic light emitting diode, the first touch electrode is in a layer that extends between the gate electrode of the sensing transistor and the semiconductor layer of the sensing transistor and that extends between a gate electrode of a transistor in at least one of the pixels and a semiconductor layer of the transistor in at least one of the pixels, and the second touch electrode is substantially coplanar with an electrode of the organic light emitting diode in at least one of the pixels.

2. The device as claimed in claim 1 , wherein: a first electrode of the sensing transistor is coupled to a driving line, and a second electrode of the sensing transistor is coupled to a sensing line.

3. The device as claimed in claim 2 , wherein the sensing transistor coupled to the driving line is maintained in an on-state during a period in which a touch driving signal is supplied to the driving line.

4. The device as claimed in claim 2 , wherein the gate electrode of the sensing transistor is coupled to a control line through which a transistor-on signal and a transistor-off signal are supplied.

5. The device as claimed in claim 1 , wherein the second touch electrode is coupled to an initialization voltage line.

6. The device as claimed in claim 5 , further comprising: an initialization switch to provide an initialization voltage to the initialization voltage line.

7. The device as claimed in claim 1 , wherein two gate insulating layers are between the gate electrode and the semiconductor layer of the sensing transistor.

8. The device as claimed in claim 7 , wherein the first touch electrode is between the two gate insulating layers.

9. The device as claimed in claim 1 , further comprising: a plurality of driving lines coupled to respective touch sensing units on each row; a plurality of control lines coupled to respective touch sensing units on each row; and a plurality of sensing lines coupled to respective touch sensing units on each column.

10. The device as claimed in claim 9 , wherein: the driving lines are coupled to the first electrode of respective sensing transistors of the touch sensing units, the control lines are coupled to the gate electrode of respective sensing transistors of the touch sensing units, and the sensing lines are coupled to the second electrode of respective sensing transistors of the touch sensing units.

11. The device as claimed in claim 10 , further comprising: a touch driver to progressively supply a touch driving signal to the driving lines; and a touch detector to detect a touch position based on a sensing signal output to the sensing lines.

12. The device as claimed in claim 11 , wherein: the touch driving signal is supplied to a specific driving line commonly coupled to touch sensing units on one row during a period, and the transistor-on signal is supplied to a control line commonly coupled to the touch sensing units on the one row.

13. The device as claimed in claim 10 , further comprising: a plurality of initialization voltage lines coupled to respective touch sensing units on each row.

14. The device as claimed in claim 13 , wherein the initialization voltage lines are coupled to respective second touch electrodes in the touch sensing units.

15. The device as claimed in claim 14 , further comprising: a plurality of initialization switches wherein each initialization switch has one end coupled to respective initialization voltage lines and another end to receive the initialization voltage.

16. The device as claimed in claim 1 , further comprising: a plurality of scan lines and a plurality of data lines coupled to the plurality of pixels; a scan driver to supply a scan signal to the scan lines; and a data driver to supply data signals to the data lines.

17. An apparatus, comprising: a touch sensor; and a pixel adjacent the touch sensor, wherein the touch sensor includes a first transistor and the pixel includes a second transistor, wherein gates of the first and second transistors are substantially coplanar on a first layer and sources and drains of the first and second transistors are substantially coplanar on a second layer, and wherein: the pixel includes an organic light emitting diode, the touch sensor includes a first electrode and a second electrode, the first electrode is in a layer that extends between the gate of the first transistor and the source and drains of the first transistor and that extends between the gate of the second transistor and the source and drains of the second transistor, and the second electrode is connected to the first electrode and is substantially coplanar with an electrode of the organic light emitting diode.